Multi-resolution Emission Inventory for China (MEIC):Introduction and recent improvement

Liu YanTsinghua University

2017.04.19

Contents

● Introduction

What is MEIC?

How does it work?

● Review of spatial proxies

What are used in China?

● Recent improvements

High resolution inventories?

Introduction: Purpose of MEIC model

● Understand magnitudes, trends, and driving forces of anthropogenic emissions in China

● Speed up the development process and update inventories timely

● Provide an online emissions dataset to the community with constant methodology and underlying data

● Support climate and air quality modeling at different spatial resolution and time scale

Introduction: Emissions data in MEIC database

l Years: 1990-

l Spatial domain: Mainland China

l Categories/Sectors: ~800 anthropogenic sources, aggregated to four sectors (Power, Industry, Residential, Transportation)

l Species: SO2, NOx, CO, NMVOC, NH3, BC, OC, PM2.5, PM10, and CO2

l VOC speciation: ~600 individual species, lumped to five mechanisms (SAPRC99, SAPRC07, CB05, CBIV, and RADM2)

l Spatial resolution: user defined

Work in progress!

Introduction: Model Framework

ID1 ID2 ID3 ID4

ID1: sectorsID2: fuel/product

ID3: technologyID4: emission control

Temporal profiles

Spatial Proxies

Activity rates (A)

Tech. Splits (X)

Removal Efficiency (ƞ)

VOC profiles

Emission Factors (EF)

Emissions = A×X×EF× (1-ƞ)

Introduction: Emission estimation & Spatial proxies

Power

Industry

Residential

Transportation

Unit based

Province based

No need

Sectors Emission estimation Spatial proxies

Population

GDP

Road network

Vehiclenumbers

……

Point sources

Surface sources

Province

to county

County to

grid

OMI proved the decreases of SO2 over Central Eastern China after 2007

Emissions

OMI

Trend in NOx emissions from MEIC and NO2 columns from satellite

Emissions data processed and delivered through an online systemhttp://www.meicmodel.org

Review: Spatial proxies used in China● Review of the spatial proxies used in regional bottom-up emission

inventories covering China

• Population

(especially total

population) is

most widely used

proxies.

● Population density←→polluted factories distribution: opposite!

Beijing Zhangjiakou

Shijiazhuang Tangshan

Review: Spatial proxies used in China

● Spatial proxies used in MEIC

Review: Spatial proxies used in China

Recent Improvement: High resolution inventories● Emissions of main sub-sectors in industry sector are estimated

based on facility. More point sources!

Coke oven

Sintering machine Blast furnace Converter

Coal

Coke

Steel rolling

Coal fired boiler

Ore

Coke oven gas Blast furnace gas

Pig iron Crude steel

Power generation

Sinter/Pellet

Coke

Gas fired machine

Material/fuel Discharging point Intermediate product Final product

( ) ( )* * 1n

n

E A EF A EF η= × + × × −∏

( )2 1EF S sr= × × −

( )* * *2 1EF S sr= × × −

( )η= × × −∏, , , ,1

i k i i k i n kn

E A EF

( )22 1

SOEF S sr= × × −

( )1PM PMEF A ar f= × − ×

2.5BC PM BCEF EF f= ×

2.5OC PM OCEF EF f= ×

( ) ( )* * 1n

n

E A EF A EF η= × + × × −∏

Eg.Steel production process

Recent Improvement: High resolution inventories

Power: SO2 Power: NOX Steel: SO2

Cement: NOX Building material: PM2.5 Industry boiler: SO2

● Emissions of main sub-sectors in industry sector are estimated based on facility. More point sources!

Recent Improvement: High resolution inventories● Emissions of main sub-sectors in industry sector are estimated

based on facility. More point sources!

15

Emission estimation NOX emission spatial distribution（High resolution-regional）

MEIC: overestimate in urban, underestimate in rural

(a) MEIC (b) High-resolution

Recent Improvement: High resolution inventories● On-road emissions of transportation sector are estimated at county

level. Temperature HumidityAltitude

Eg. Environmental compensation factors matrix are built at countylevel, which can improve the spatial and temporal precision。

● On-road emissions of transportation sector are estimated at countylevel.

Spatial proxies

Emission factor

Activity at county level

Emission standards

Road network

Compensation factors

Recent Improvement: High resolution inventories

Recent Improvement: High-resolution inventories● Spatial proxies used in MEIC and our new high-resolution inventory

for Hebei province, 2013(HB-EI)

Recent Improvement: High-resolution inventories● Spatial correlations between gridded emissions of HB-EI and

various spatial proxies.

NL: nighttime light

TP: total population

UP: urban population

RP: rural population

RN: road network

Recent Improvement: High resolution inventories

● Evaluations against in situ measurements for atmosphericmodeling (CMAQ) using MEIC and HB-EI

Regional inventory High-resolution inventory

PM2.5 Observation

O3 Observation

PM2.5

O3

• Resolution: 36km(region

scale)→4km(city scale),

the simulation bias with

regional inventory

increases, but decreases

with high resolutioninventory.

• At 4km, using high

resolution inventory can

can shorten the PM2.5

simulation bias from31%

to -2%；O3 from -17% to -

9%。

Thanks for your attention!