Air Pollution

Outline

Classification Composition of air Sources of air pollution Effects Controls Major air pollution problems Air policy and Legislation Air Pollution Index (API)

Types of air pollution

Personal air pollution Occupational pollution Community / environmental air pollution

Sources

Natural Man-made

Natural

Wind-blow dust Smoke Gases from swamp Fog volcanic

Natural Pollutants

SO2

H2S CO NO,NO2

NH3

Hydrocarbon CH4

CO2

O3

Man-made

Dust Combustion Manufacturing Agricultural Nuclear energy

Man-made Pollutants

Particulates Oxides of sulphur and nitrogen CO2 Organic vapour Vapour with traces of heavy metal H2S Radioactive

Effects

Vegetation Human beings and animals Materials Health

Materials

Abrasion Deposition Chemical attack Corrosion

Health

Particulates – respiratory tracts SO2 – respiratory, asthematic CO2, CO - No2 - respiratory O3 - respiratory Pb – nervous and cardiovascular

Control

Zoning Control at source Use device and equipment Use high stacks vegetation

Zoning

Control at source

Replace Reengineering Redesign Reduce

By device

Gravitational settling chamber Inertial collectors Wet collectors Fabric Electrostatic precipitators

Control at construction site

Legislation Dust reduction measures Stop malpractice Notify Environmental Protection Dept

Dust reduction measures

Wet by water spray Provide hoarding to fence off the site Product dust screen Cover dusty materials on site and vehicles Dispose dusty materials correctly Cover unfinished site formation work Provide vehicle wash basin

Stop malpractice

Do not use compress air for cleaning Do not operate without any controls Do not stockpile dusty materials without

proper procedures Do not blast on strong wind signals

Notify EPD

Site formation Reclamation Building demolition Tunnel work Building construction Road construction

Major Problems

Acid Rain

Ozone depletion

Green House Effect

Indoor Air Pollution

Acid Rain

pH as low as 3 Mainly due to Industrial pollutants No2, So2 and volatile organic vapour are

converted to acidic compounds

Effects of Acid Rain

Natural life Building materials Crops and vegetation Cause deteriation of soil

Ozone depletion

Ozone exist in stratosphere (outer atmosphere)

Ozone is used to shield ultra-violet light (short-wave length)

Ozone is depleted by CFC (carbo-halogen-compound)

Nitrous oxide contribute to depletion of ozone

Effects of Ozone depletion

Skin cancer Eye sickness Kill phytoplankton

Decrease in food supplies More CO2

Green House Effects

Absorb long-wave (ultra-red) Let in short-wave and absorb long wave Acts like a glass in a green house Cause global warmness

Effects of Green house

Rise of water temperature and causing global climate changes

Indoor Air Pollution

CO Formaldehyde Radon NO2

Effects of indoor air quality

Sick building syndrome

Control

Control

Land use planning Enforcement of Air Pollution Ordinance AQO Restrict certain specified process/trades

Hong Kong Air Quality Objective

SO2 TSP RSP NO2 CO Ozone Lead

AQO

Exposure in hours Exposure quantity

Air Pollution Index

What is API ?

The API is an index that converts several pollutants into a value ranging from 0 – 500

API forecast serves as a warning to the public

How is it determined It is calculated by comparing the

measured concentration of major air pollutants with their respective health related AQO.

These pollutants are NO2, SO2, ozone, CO, and RSP.

APIs for each of these pollutants are calculated and the highest API number is reported.

API’s are reported hourly.

How to use APIs ?

The API values are divided into 5 bands. We can relate API to the followings

Air Quality status Air Pollution level Health implication Actions recommended

Locations of monitoring

Roadside API