It's normal for air quality to vary in a region

Variations in air quality readings

With reference to Daniel Bardsley’s article Bangladesh, Pakistan and India have world’s most-polluted air, report finds (March 19): The article mentions pollution rates in Ras Al Khaimah, citing data from the air purifier company IQAir, which could be perceived to have a vested interested in promoting the sales of their own products to concerned individuals. In Ras Al Khaimah, we have the tools to accurately measure air quality (AQ data). For several years we have been plagued by individuals reporting poor AQ and referring to the IQAir website as the source of their information.

When we review AQ from our regularly maintained and calibrated national stations, we typically find that the IQAir company-generated values are inflated. As I wrote this letter, I checked the IQAir website, which showed the air quality index in my area in Ras Al Khaimah as being 105 – unhealthy for sensitive groups. However, our national stations showed the index as 37 (good). I walked outside and saw the air was still with no visible dust and my breathing was not affected in any way. In layman’s terms, the quality was obviously good.

Any reasonable person can expect there to be small variations in AQ depending upon where the measurement is taken, but the magnitude of the difference between the IQAir data and the national data can only mean one thing: the IQAir sensors are inaccurate and/or defective, and certainly do not give a representative reading of an entire region or emirate.

Dr Saif Al Ghais, Director General, Ras Al Khaimah Environment Protection and Development Authority

An unusual earthquake in Taiwan

With regard to the report Taiwan earthquake: Nine dead and 800 injured in 7.4-magnitude quake (April 3): This was a scary read. I was struck by the fact that this was the most powerful quake that Taiwan witnessed in 25 years, sparking tsunami warnings. I pray for the departed and the speedy recovery of the injured. K Ragavan, Bengaluru, India

Gaza's mounting tragedies

With regard to Holly Johnston and Thomas Helm's report Aid to Gaza threatened after Israeli strike forces World Central Kitchen to pause work (April 2): This is so horrible and unacceptable. I don't know which words to use any more for the carnage in Gaza and when world leaders are going to be able to put an end to Israel's actions.

Nikolina Pazanin, Larnaca, Cyprus

My heart goes out to the families who have lost so much in these senseless tragedies, this one being just the latest. I pray for a long overdue ceasefire and peace.

P S Bloom, Yorkshire, UK