A Guide to Air Quality and Our Health

Introduction

What is the SLAQI?
The SLAQI is an index for reporting daily/weekly air quality. It tells you how clean or polluted our air is, and what associated health effects might be a concern for us. The SLAQI focuses on health effects, which we may experience within a few hours or days after breathing polluted air. AirMAC calculates the AQI for five major air pollutants regulated by the National Environmental Act No. 47 of 1980 and regulations made under Section 32: ground-level ozone, particle pollution (also known as particulate matter), carbon monoxide, sulfur dioxide, and nitrogen dioxide. For each of these pollutants, there are established national ambient air quality standards to protect public health. These standards are gazetted in the government gazette of 20.12.1994.

How does the SLAQI work?
Think of the SLAQI as a yardstick that runs from 0 to 500. The higher the AQI value, the greater the level of air pollution and the greater the health concern. For example, an SLAQI value of 50 represents good air quality with little potential to affect public health, while an SLAQI value over 300 represents hazardous air quality.

An SLAQI value of 100 generally corresponds to the national air quality standard for the pollutant, which is the level EPA has set to protect public health. SLAQI values below 100 are generally thought of as satisfactory. When SLAQI values are above 100, air quality is considered to be unhealthy, at first for certain sensitive groups of people, then for everyone as SLAQI values get higher.

Understanding the SLAQI
The purpose of the SLAQI is to help you understand what local air quality means to your health. To make it easier to understand, the SLAQI is divided into six categories:

Sri Lanka Air Quality Index (AQI) Values Levels of Health Concern Colors

Sri Lanka Air Quality Index	Interpretation	Color Code
0 to 50	Good	Green
51 to 100	Moderate	Yellow
101 to 150	Unhealthy for Sensitive Groups	Pink
151 to 200	Unhealthy	Red
201 to 300	Very Unhealthy	Dark Red
301 to 500	Hazardous	Maroon

Prepared by Dr. Ruwan Wijayamuni (MD. MPH. MSc Comm. Med.)