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Observational analysis of biomass burning impacts to Hong Kong Yun Fat LAM, Irene Yeung and Tobi Morakinyo Irene Yeung 10 Sep 2015 7-SEAS International Workshop 23 September 2016 Introduction Biomass burning: Forest, grassland, domestic

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Observational analysis of biomass burning impacts to Hong Kong

Irene Yeung 10 Sep 2015

Yun Fat LAM, Irene Yeung and Tobi Morakinyo 7-SEAS International Workshop 23 September 2016

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School of Energy and Environment, City University of Hong Kong

Introduction

Biomass burning:

  • Forest, grassland, domestic and open burning
  • Affect air quality, human health, visibility and global climate
  • Global source of aerosol and trace gases
  • Significant contribution of VOCs/PM/CO to the atmosphere

Air quality impacts:

  • Local and regional CO and PM pollution
  • Main precursors: NOx, CO, CH4 and VOCs
  • Tropospheric O3: product of photochemical reactions from CO
  • Long-range transport led to O3 and PM pollution in downwind countries

Source:http://news.stanford.edu/news/2014/july/images/14125-biomass_banner.jpg

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School of Energy and Environment, City University of Hong Kong

Southeast Asia Burning Emissions)

  • March and April are referred to

the start of spring farming season in SEA peninsula (Pochanart et al., 2001; Gadde et al., 2009)

  • Annual profile of biomass burning

dry matter (DM) emission in SEA

  • Peak at spring
  • Dry season: October to May

(from Global Fire Emission Database)

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School of Energy and Environment, City University of Hong Kong

  • 1. High pollutant concentrations in the spring

Examples from Tap Mun station:

  • O3: 263 mg/m3
  • PM10: 90 mg/m3
  • 17 incidents of “high” and 3 incidents of “very high” of Air Quality Health

Index (AQHI) in April 2015

  • 2. Potential reasons

I.

Stratospheric ozone (STE from North)

  • II. Long-range transport from PRD
  • III. SEA biomass burning emissions

Hong Kong Situation

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School of Energy and Environment, City University of Hong Kong

Seasonal change of wind pattern (South China Sea)

Summer Monsoon (SW): bring clean maritime air to SCS Winter Monsoon (NE): bring industrial pollutants to SCS ∴ Air pollution episodes mainly take place in winter

Source: http://www.hko.gov.hk/blog/en/archives/00000071.htm

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School of Energy and Environment, City University of Hong Kong

Transport Mechanism

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School of Energy and Environment, City University of Hong Kong

[1] Vertical Advection

  • Fire buoyancy - Height of emission

plume = 2~5km

  • ~40% directly injected to the free

troposphere (Jian and Fu, 2013)

  • Reach the free troposphere

Source: http://patentimages.storage.googleapis.c

  • m/thumbnails/US6809743B2/US06809

743-20041026-D00002.png https://www.bnl.gov/envsci/aerosol/c ampaigns/bbop/index.php

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School of Energy and Environment, City University of Hong Kong

Transport Mechanism

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School of Energy and Environment, City University of Hong Kong

Transport Mechanism

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School of Energy and Environment, City University of Hong Kong

[2] Transport to Higher Latitude

1.

The southwesterly flow confluence boundary layer coupling with a well-

  • rganized convergent center at the Indochina peninsula in March and

April

2.

Encourage an ascending motion to form the upward branch at the burning region (Lin et al., 2013; Yen et al., 2013)

3.

Pollutants were brought up to higher latitude regions

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School of Energy and Environment, City University of Hong Kong

Transport Mechanism

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School of Energy and Environment, City University of Hong Kong

[4] Downdraft to Surface

  • Cold surge anticyclone:

Southward cold air over northern provoke cold surge

  • Cold surge and warm

front meets

  • Cold air slides under the

warm air and bring biomass pollutants aloft to the surface of Hong Kong

Source: http://www.wxkph.info/#!ne-monsoon-and- cold-surges/czz9

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School of Energy and Environment, City University of Hong Kong

Observation analysis/impact study

  • Impacts on regional background pollution
  • Study on Spring-time biomass burning events
  • Impacts on local air quality at South China Seas
  • Study period: March – May 2012-2015
  • O3, CO, PM, NOx, SO2

Study Analysis

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School of Energy and Environment, City University of Hong Kong

Study Domain

Source region Receptors

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School of Energy and Environment, City University of Hong Kong

Selected Stations

List of stations: Hong Kong  Tai Mo Shan  Causeway Bay  Tap Mun Taiwan  Lulin

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School of Energy and Environment, City University of Hong Kong

Hong Kong stations

[1] Tai Mo Shan Station

  • ~1km MSL
  • Spring-time PBL around

400-650 m, in most time less then 800m

  • Well represent the air

above the PBL

  • Data available until 2015
  • Equipment: O3, CO, PM,

NOx, SO2

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School of Energy and Environment, City University of Hong Kong

Results discussion

  • 1. Background contribution to SCS
  • 2. Event identification and its impact
  • 3. Impacts of downdraft meteorological condition
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School of Energy and Environment, City University of Hong Kong

[1] Background Contribution

  • Identify source region
  • Perform HYSPLIT particle dispersion model

(1) With vertical mixing below 800m (2) Without vertical mixing or passing through HK domain

  • Identify background enhancement through local

monitoring data

– Pure transport, regardless of SEA emissions

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School of Energy and Environment, City University of Hong Kong

Identify source region

Statistics Dispersion Magnitude (kg DM/m2/month) Mean 0.135 Upper 5.0% 0.658 Upper 1.0% 1.440 Upper 0.1% 2.911

  • Six locations are chosen by the Upper 1% of March and April DM sum
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School of Energy and Environment, City University of Hong Kong

Perform HYSPLIT

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School of Energy and Environment, City University of Hong Kong

Background Contribution (mg/m3)

  • 20%
  • 15%
  • 10%
  • 5%

0% 5% 10% 15% 20% 200 400 600 800 1000 1200 1400 TMS_CO CWB_CO TM_CO LL_CO

CO (-5.5 to 135)

  • 20%
  • 15%
  • 10%
  • 5%

0% 5% 10% 15% 20% 20 40 60 80 100 120 TMS_O3 CWB_O3 TM_O3 LL_O3

O3 (-0.8 to 6.8)

  • 20%
  • 15%
  • 10%
  • 5%

0% 5% 10% 15% 20% 5 10 15 20 25 30 35 40 45 50 TMS_PM2.5 CWB_PM2.5 TM_PM2.5 LL_PM2.5

PM2.5 (-3.1 to 4.0)

  • 20%
  • 15%
  • 10%
  • 5%

0% 5% 10% 15% 20% 10 20 30 40 50 60 70 80 TMS_PM10 CWB_PM10 TM_PM10 LL_PM10

PM10 (0.1 to 5.5)

ALL WithoutVM WithVM Diff.

Concentration (𝜈g/m3)

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School of Energy and Environment, City University of Hong Kong

∆𝑸𝑵𝟑. 𝟔 ∆𝑸𝑵𝟐𝟏 𝒔𝒃𝒖𝒋𝒑 (𝐔𝐍𝐓)

  • Represent the characteristics of the combustion sources
  • Decreas of ∆ PM2.5/ ∆ PM10 ratio
  • Higher proportions of PM10 aerosols
  • Contribution of different foreign sources in vertical mixing cases

PM2.5 = 0.501 (PM10) + 1.97 R² = 0.83 10 20 30 40 50 60 70 80 50 100 150 PM2.5 PM10

cases with vertical mixing PM2.5/PM10 ratio

PM2.5 = 0.604(PM10) + 0.4911 R² = 0.98 10 20 30 40 50 60 70 80 50 100 150 PM2.5 PM10

cases without vertical mixing PM2.5/PM10 ratio

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School of Energy and Environment, City University of Hong Kong

Results discussion

  • 1. Background contribution to SCS
  • 2. Event identification and its impact
  • 3. Impacts of downdraft meteorological condition
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School of Energy and Environment, City University of Hong Kong

Case Identification:

  • 1. Particle dispersion starting from SEA pass over HK
  • 2. Backward trajectory
  • 3. HK meteorological conditions for downdraft
  • 4. High level of fire emissions recorded at SEA areas

[2] Episodic event

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School of Energy and Environment, City University of Hong Kong

Example for Cases Identification (2013 March W3)

SEA BB DM emissions (kg/day/m2) HK back trajectory SEA pacticle dispersion HK Meteor. Condition Greater than March and April lower quartile? From SEA? Arrice HK <800m? Vertical mixing? 13/3/13 Y Y 13/3/14 Y Y Y Y 13/3/15 Y Y Y Y 13/3/16 Y Y Y 13/3/17 Y Y 13/3/18 Y Y

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School of Energy and Environment, City University of Hong Kong

HYSPLIT

  • From source
  • Kyaukme, Myanmar,

Burma (22.625, 96.625)  Uplifted and transported northeastward  Reached TW and started to descend to south  Due to the subsidence as a result of the cold surge anticyclone

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School of Energy and Environment, City University of Hong Kong

Backward Trajectory From HK

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School of Energy and Environment, City University of Hong Kong

Southeast Asia Biomass Burning Emissions Profile

March-April Mean=0.66 March-May Mean=0.45

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School of Energy and Environment, City University of Hong Kong

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School of Energy and Environment, City University of Hong Kong

Hong Kong Meteorological Conditions

  • Air mass originated from the free atmosphere was transported to

the surface (cold, dry and higher speed)

– Downdraft

  • Temperature declined
  • Humidity dropped
  • Wind speed increased
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School of Energy and Environment, City University of Hong Kong

Effects of HK Air Quaity

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 3 5 7 9 1113151719212325272931 PM25/PM10 (ug/m3/ug/m3) Day 20 40 60 80 100 120 140 160 1 3 5 7 9 1113151719212325272931

concentration(𝜈g/m3)

2013 March TMS

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 PM25/PM10 (ug/m3/ug/m3) Day 20 40 60 80 100 120 140 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31

concentration(𝜈g/m3)

2013 March TM

CO(10ug/m3) O3(ug/m3) PM25(ug/m3) PM10(ug/m3)

  • During episode

period

  • CO,O3,PM2.5 and

PM10 increase

  • PM2.5/PM10 ratio

decrease

  • Further study for other biomass burning emission tracer
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School of Energy and Environment, City University of Hong Kong

Summary

2012 2013 2014 March April March April March April

W1 W2 W3 W4 W1 W2 W3 W4 W1 W2 W3 W4 W1 W2 W3 W4 W1 W2 W1 W4 W1 W2 W3 W4

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School of Energy and Environment, City University of Hong Kong

Results discussion

  • 1. Background contribution to SCS
  • 2. Event identification and its impact
  • 3. Impacts of downdraft meteorological

condition

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School of Energy and Environment, City University of Hong Kong

HK Local Air Pollution Enhancement by Downdraft

  • 6%
  • 4%
  • 2%

0% 2% 4% 6% 8% 10% 12% 14% 16% 500 1000 1500 2000 2500 3000 TMS_CO CWB_CO TM_CO

CO

  • 12%
  • 10%
  • 8%
  • 6%
  • 4%
  • 2%

0% 2% 4% 6% 10 20 30 40 50 60 70 80 90 TMS_O3 CWB_O3 TM_O3

O3

0% 5% 10% 15% 20% 25% 10 20 30 40 50 60 TMS_PM25 CWB_PM2.5 TM_PM2.5

PM2.5

0% 2% 4% 6% 8% 10% 12% 14% 10 20 30 40 50 60 70 80 TMS_PM10 CWB_PM10 TM_PM10

PM10

WithVM WithoutVM Diff.

Concentration (𝜈g/m3)

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School of Energy and Environment, City University of Hong Kong

Summary

TMS CWB TM CO O3 PM2.5 PM10 CO O3 PM2.5 PM10 CO O3 PM2.5 PM10

Background contribution 15.4 6.6 1.3 3.0 16.5

  • 0.1

1.6 3.1 112.6 2.3 4.0 5.6 Episodic event 243.3 21.1 9.5 15.7 28.1 5.3 8.5 19.9 184.3 17.6 11.0 22.5 Downdraft meteorologic al condition 39.7 2.8 0.0 1.3

  • 39.8 -2.2

4.9 5.8 88.9 0.8 6.3 6.4

Concentration (𝜈g/m3)

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School of Energy and Environment, City University of Hong Kong

Acknowledgement

  • Environmental Conservation Funds
  • Guy Carpenter Asia-Pacific Climate Impact Centre

(GCACIC)

  • Hong Kong Environmental Protection Department

(Peter Louie)

  • National Taiwan University (George Lin; Ming-Tung

Chuang)

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School of Energy and Environment, City University of Hong Kong

Thank you !

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School of Energy and Environment, City University of Hong Kong

[3] Impacts of Meteorological Conditions

  • Sorting with different groups by Hong Kong meteorological

data (wind speed, temperature and humidity)

(1) With downdraft meteorological conditions (2) Without downdraft meteorological conditions