Colombo air quality map

What information can be gleaned from the air pollution map for Colombo?

Once the main city page is opened, it is easy to find the air quality map for Colombo as it will be towards the top of the opening page; very often at the top left-hand side. When the map is chosen, the user will be directed to a new page which is exclusively dedicated to the air quality of the city and surrounding areas.

Possibly the first thing to notice will be the overall colour of the background of the map. This colour is an overall reflection of the air quality. It is currently pale green which indicates “Good” quality air. The meaning of the various colours is explained in the legend at the foot of the page. Colours range from pale green to dark maroon.

Several coloured discs will be seen, each of which displays a number. This is the US AQI reading which is another indication of the air quality. The lower numbers represent cleaner air. The whole system is endorsed by the World Health Organisation (WHO). It is calculated by measuring the levels of up to six of the most prolific pollutants found in the city air. It can then be used as a standard when comparing air quality in other cities across the globe.

Midway through the third quarter of 2022, Colombo was enjoying a period of “Good” quality air with a US AQI reading of 31. The main pollutant was noted to be PM2.5 with a level of 7.5 µg/m³. This is just one and a half times higher than the suggested level of 5 µg/m³ by the WHO.

Can any other information be gathered from the air pollution map for Colombo?

The air pollution map for Colombo is easy to open from the main city page. Once opened, the reader will notice four options which are listed on the left-hand side of the page. These can all be deselected if required.

The first option shows the location of the ground-level air monitoring stations. These are represented by coloured discs and some of these may appear to be overlapping each other, but when the map is expanded, the discs will begin to separate and become easier to see.

The second option shows the position of any fires that might be burning in the vicinity. This is especially useful when looking at option four which shows the direction of the prevailing winds. Together they give a good indication as to whether the city will be affected by smoke or not.

The third option is the most dramatic as it changes the background colour of the map to reflect the overall quality of the air. It is currently a greenish colour which indicates “Good” air quality across the region. Some viewers may find the colour a little confusing, but it can be deactivated and the map will revert to more conventional colours and become easier to understand.

Directly beneath the map is the number of stations which provide the air quality data. It also shows who owns or operates them.

Across on the right-hand side of the page is found a table which shows the ranking of cities across the world, based on the quality of their air. The most heavily polluted ones will appear at the top of the table. Some cities on the list may surprise you as they are not often considered to be dirty cities, but the comparison between cities can be very interesting.

Can areas of high pollution be identified on the air quality map for Colombo?

As previously stated, the colour on the discs is a direct indication of the air quality in that area. If they are all the same colour, then look for the disc which is showing the highest number as this will be the most polluted area.

However, directly below the map is a list of all the stations ranked in order of their levels of pollution. Currently, the most polluted area is in the vicinity of the US Embassy in Colombo. It shows a US AQI reading of 41 which is classified as “Good” quality air, even though it ranks as being the most polluted.

Reading further down the page can be seen all the stations listed according to their popularity. Once more it is the US Embassy in Colombo with over 27,000 followers.

Is it possible to see where the pollution comes from on the air quality map for Colombo?

Several types of research and studies have shown that the level of air pollution in the city of Colombo has increased in the last few decades due to the growth of traffic density, industries, domestic and commercial activities in and around the city. Air pollution levels are relatively higher in areas with heavy traffic within the city as compared to other surrounding areas.

Among the many ways to reduce emissions per kilometre driven are emission standards for new vehicles, pollution control inputs, fuel quality improvements, increased maintenance standards, use of cleaner fuels and more efficient engines. Likewise, demand and supply management including vehicle ownership and controls, carpooling, public transport improvements, Park and Ride facilities, pricing, road sharing for bicycles and other vehicles to reduce driving kilometres.

PM2.5 is often mentioned on the air pollution map for Colombo, but what is it?

Emissions from the combustion of gasoline, oil, diesel fuel or wood produce much of the PM2.5 pollution found in outdoor air, as well as a significant proportion of PM10. PM10 also includes dust from construction sites, landfills and agriculture, wildfires and brush/waste burning, industrial sources, wind-blown dust from open lands, pollen and fragments of bacteria.

PM may be either directly emitted from sources (primary particles) or formed in the atmosphere through chemical reactions of gases (secondary particles) such as sulphur dioxide, nitrogen oxides, and certain organic compounds. These organic compounds can be emitted by both natural sources, such as trees and vegetation, as well as from man-made (anthropogenic) sources, such as industrial processes and motor vehicle exhaust.

For PM2.5, short-term exposures (up to 24-hours duration) have been associated with premature mortality, increased hospital admissions for heart or lung causes, acute and chronic bronchitis, asthma attacks, emergency room visits, respiratory symptoms, and restricted activity days. These adverse health effects have been reported primarily in infants, children, and older adults with pre-existing heart or lung diseases.