At the end of 2018, Lahore witnessed the worst air quality in the world with AQI 256 (Air Quality Index) in December and 315 in November. However, the city ranked 4^th polluted city in the world with AQI coming down at 172 during the last week. 172 is an average index but some areas in the city are still above 200, while Karachi stands at 10th with AQI 164. There are certain reasons involved in reducing AQI, however, the current pollution level is still threatening human lives.

The air quality index (AQI) is an internationally acknowledged gauge of pollution levels. Once AQI values go over 100, the quality becomes unhealthy, predominantly for sensitive groups, but if AQI values go further higher it becomes injurious to everyone.

Identifying and quantifying particulate matter (PM) in the atmosphere is the key to determine air quality. The number (usually 10 or 2.5) indicates the size of the particulates monitored. PM10 refers to particles with diameter 10 µm or smaller, and PM2.5 to particles with diameter 2.5 µm or smaller.

According to WHO (World Health Organization) particulate matter (PM) are particles composed of sulphate, nitrates, ammonia, sodium chloride, black carbon, mineral dust and water. Particles with a diameter of less than 10 microns (PM10), including fine particles less than 2.5 microns (PM2.5), pose the greatest risks to health as they are capable of penetrating people’s lungs and bloodstream.

Sources of PM include fuel combustion from motor vehicles, heat and power generation (e.g. oil and coal power plants and boilers), industrial activities (building, mining, manufacture of cement, ceramic and bricks, and smelting), solid-fuel (coal, lignite, heavy oil and biomass), municipal and agricultural waste sites and waste burning, residential cooking, heating, and lighting with polluting fuels.

WHO data shows 7 million people die in the world every year from exposure to fine particles in polluted air that lead to diseases like lung cancer, chronic obstructive pulmonary diseases and respiratory infections, including pneumonia. Pakistan has some of the worst air quality in the world. On average, Pakistanis are exposed to PM2.5 levels more than 6.5 times the level determined safe by the World Health Organization. As a result, Pakistanis drop 2.5 years on their life expectancy, and in 2012 approximately 60,000 Pakistanis died from air pollution, one of the highest death counts in the world.

Lahore-based environmentalist Asif Ali Sial says the environment all around in the country is highly polluted. "Substandard fuels, industry within city and without emission control systems, burning of solid waste and ineffective EPA (Environment Protection Authority) are the leading causes of severe environmental pollution in Lahore."

"Burning of solid waste puts pollutants like carbon dioxide, mercury and acid into the air. Nitrogen dioxide, sulphur dioxide, lead and carbon monoxide are the main pollutants due to heavy traffic. That is why the WHO data shows that air pollution in Lahore accounts for rapid sprout in fatal health issues such as asthma, eye infections, allergies, cardiac diseases, respiratory infections and even premature deaths."

Environment Protection Department (EPD) data shows that year 2017 was the worse in terms of air pollution when AQI of Lahore touched 400 and an average level remained 386 throughout the year.

"The steps taken in 2018 to reduce pollution level include the shutdown policy of factories and steel mills in winter that use furnace oil and inept boilers; brick kilns operating without zig zag technology were also padlocked; article 144 was imposed on burning solid waste," director EPD Naseem-ur-Rehman tells TNS.

Air pollution is a complex mixture of particulates and gases. 9 out of 10 people breathe air containing high levels of pollutants. 91 percent of the world’s population lives in places where air quality exceeds WHO guideline limits. That is why rather relying on just one type of sensor, data should be collected from multiple complementary instruments and combined to obtain a comprehensive understanding of the composition and movement of the atmosphere.

There are only seven monitors working in the Punjab province; four in Lahore and one each in Faisalabad, Gujranwala and Multan. "Two monitors in Lahore are out of order. Environment Protection Department (EPD) is planning to implant monitors in all districts, nevertheless, the department is yet not successful in generating funds," Naseem-ur-Rehman adds.

Apart from the government’s monitors and sensors, private sector has implanted both to gauge pollution level. However, Rehman considers those substandard and main cause of releasing wrong data that creates panic all around. "EPD is not against implanting monitors and sensors but the equipment must be according to the international standard to avoid any wrong information."

However, Environmental Consultants Association of Pakistan (ECAP) disagrees with Naseem-ur-Rehman. President ECAP Aleem Butt tells TNS that EPD’s monitors and sensors can’t gauge accurate level of pollution. "Four monitors in Lahore cannot show us the average index of air pollution in the city. Moreover, there are no sensors inserted that can measure the level of individual pollutant in the air necessary to bring solutions to the polluted air."

He adds, "Fundamentally, in the absence of such sensors and ill-equipped monitors, errors are always found in the AQI monitoring systems installed by EPD. Contrary to this private sector owns effective and up-to-date equipment to measure air pollution."

Environmentalists say weather conditions play a vital role in the fluctuation of air pollution.

Director Regional Meteorological Department (PMD), Lahore, Mehar Shahzad Khan, tells TNS that summer always seems to drive out the dense clouds of pollution as summer air is in fact cleaner. "During summers, pollution levels decrease as the warmer air rises up freely, making the boundary layer thicker, and providing enough space for pollutants to disperse. During the winter, cold air traps pollutants close to the ground, a process called ‘inversion’. Summer heat prevents this inversion, which does improve the air quality."

"However, the pollution, especially over Lahore, gets magnified during the post-monsoon months due to a combination of atmospheric and human factors. During winters the planetary boundary layer is thinner as the cooler air near the earth’s surface is dense. The cooler air is trapped under the warm air above that forms a kind of atmospheric ‘lid.’"

Khan adds, "Wind direction is also an important factor in winter that increases pollution causing smog. This winter, wind direction was northern instead of eastern which comes from India and considered one of the main causes of smog in the previous years."

According to SUPARCO (Pakistan Space and Upper Atmosphere Research Commission), Pakistan is confronted with a number of severe environmental problems such as degradation of natural resources, industrial and vehicular pollution, pollution of marine environment and degradation of human health. The annual cost of environmental degradation in the country is about 4.3 percent of GDP (US $ 4.3 billion). Specific examples are; air, land and water degradation, drought and desertification, water logging, forest depletion, loss of biodiversity, vehicular and industrial pollution and climate change.

Air pollution is an invisible killer that lurks all around us, preying on the young and old people alike. Environmentalists and health experts suggest local and national policies and investments supporting cleaner transport, energy-efficient housing, power generation, industry and better municipal waste management to effectively reduce key sources of air pollution.