Cloud seeding and air pollution

Recent poor air quality in regions such as Pakistan, China and the UAE has led to the use of artificial rain or ‘cloud seeding’ to reduce the amount of air pollution and in some cases, smog.

This month, Pakistan undertook its first-ever artificial rain experiment over Lahore, a city frequently battling severe smog. While primarily aimed at reducing air pollution, the results were inconclusive. The UAE partnered with Pakistan on the Lahore experiment to share expertise.

China has previously used cloud seeding to increase rainfall in agricultural regions but also experimented with its use for air quality improvement during major events like the 2008 Beijing Olympics.

What is cloud seeding?

Artificial rain, also known as cloud seeding, is a weather modification technique aimed at enhancing precipitation by dispersing substances into the air that serve as cloud condensation or ice nuclei.

How does it work?

Increased precipitation can reduce certain types of air pollutants.

It can have a washing effect to help remove particulate matter and pollutants from the air by acting as a natural scrubber. As raindrops fall through the atmosphere, they can capture and carry down particles and pollutants, effectively cleaning the air.

Once landed, the rain can help to settle particulate matter and pollutants from the atmosphere. It can also react with certain pollutants such as sulphur dioxide and form less harmful compounds in a process called ‘wet disposition’.

Improved Visibility: Heavy rain can significantly improve visibility by washing away the haze of airborne particles. This can be especially beneficial in areas with frequent smog or pollution episodes.

What are the pros and cons?

While artificial rain can potentially assist in these processes, it’s important to note that its effectiveness in mitigating air pollution may vary depending on the types and sources of pollutants. Additionally, cloud seeding is a complex and debated technique with potential environmental and ethical concerns. It’s crucial to consider the broader implications and conduct thorough research before implementing such measures on a large scale.

Here are some limitations:

Temporary Relief: The effects of artificial rain are usually temporary, lasting for a few hours to a few days. Once the rain stops, pollution levels can rise again if the original sources remain unaddressed.

Not Effective for All Pollutants: Certain gaseous pollutants like ozone and carbon monoxide are not easily washed away by rain. Additionally, heavy rain can sometimes lead to flash floods, causing other environmental problems.

Ethical Concerns: There are concerns about the potential ethical implications of manipulating weather patterns, particularly if it could have unintended consequences for other regions.

Technical Challenges: Successfully inducing rain requires specific weather conditions and careful targeting of clouds. It’s not always a guaranteed method and can be expensive to implement.

Is it worth it?

Here are some additional things to keep in mind:

• Artificial rain is mainly effective for larger particles like PM10 and PM2.5, less so for finer particles like PM2.5-10.
• The effectiveness of artificial rain can vary depending on factors like the type of pollution, cloud conditions, and wind patterns.
• Research is ongoing to improve the techniques and understanding of cloud seeding for pollution control.

Addressing the root causes of air pollution, such as reducing emissions from industrial processes, vehicles, and other sources, remains a more sustainable and comprehensive approach to improving air quality.

Picture by: pexels-eberhard-grossgasteiger-1019991