Roadside emissions tests keep a track of the pollution levels in the city so appropriate action can be taken to control it


Vehicle emissions tests to reduce the environmental impact of car exhaust fumes can also be repurposed to examine fuel consumption and improve vehicle fuel efficiency.

Mandatory emission testing legislation implemented in 2008 in the Western Province and subsequently introduced to other provinces has helped to preserve the ambient air quality of Sri Lanka despite increases in vehicle population. In addition to reducing harmful exhaust and improving engine lifespan, emission testing can also increase vehicle fuel efficiency. 

Emission test centres run by Drivegreen issue an Estimated Fuel Efficiency Report with each emission test, providing motorists with a useful guide to how much fuel a vehicle wastes and identifying how they can reduce the amount wasted. Up to 25 percent of the fuel energy output is wasted, but simple maintenance programmes, like the regular cleaning of air and oil filters, can reduce fuel consumption significantly.

Vehicles are one of the primary contributors to air pollution, but good emission monitoring mechanisms along with clean vehicle and fuel technologies can significantly reduce harmful exhaust, as well as fuel wastage. 

Widespread emission testing and regular maintenance can reduce the country’s overall fuel consumption, which will also reduce overall emissions further. Efficient vehicles with better fuel mileage burn less fuel for the same power, directly reducing the exhaust gases emitted. Similarly, other measures to get better mileage such as improving AC and lights efficiency, keeping tyres properly inflated and using the correct motor oil grade, all lower emissions as well. 
A report released last year by the World Health Organisation (WHO) showed that chemicals and particle matter released in exhaust gas adversely affect health, leading to respiratory and circulatory disorders. 

Numerous studies have highlighted that air pollution contributes to global warming and harms local ecosystems. Despite an increase in the number of vehicles in Sri Lanka, total emissions have remained stagnant. This is attributed in part to mandatory annual emission tests required of all motorists and the roadside emission tests which monitor emissions on an ongoing basis.  

The harmful substances of exhaust gas are carbon monoxide from incomplete combustion, hydrocarbons from unburnt fuel, nitrogen oxides from excessive temperature and pressure and particulate matter. Emission tests show how much of these chemicals a car produces and how it can be reduced. Carbon monoxide and nitrogen oxides in vehicle exhaust are also recognized as contributors to climate change. 

Although modern vehicle technologies have improved engine efficiency and reduced the amount of toxic chemicals generated, specific mechanisms to remove and mitigate them are still required. Exhaust gas recirculation reduces the peak combustion temperature and prevents the formation of nitrous oxides and catalytic converters use a combination of catalysts to convert carbon monoxide, hydrocarbons and nitrous oxides into less harmful gases. Often, catalytic converters also use a secondary air injection into the exhaust ports to allow hydrocarbons to burn fully.