The implementation of new rules like the odd-even rule in Delhi and daily newspapers dedicating a good 6″x 6″ box showing pollution levels in major Indian cities, on their front page has suddenly brought air pollution in the forefront of our debates. It does not help to notice that several International health agencies had marked New Delhi as the No.1 most polluted city in the world. Even smaller cities like Gwalior and Kanpur feature in the top 10 most polluted cities around the world. Air pollution is an invisible demon to the naked eye and we would have ignored it too were it not for the Crusaders PM 2.5 Detector that we are reviewing.


Of course the reasons for this pollution are multiple but so are the consequences. Breathing in these cities has been compared to breathing in smoker’s room of a pub, only this time you are breathing such harmful air 24×7.

Air pollution contains many components. These contain various Particulate Matter (PM) particles and even aerosols like deodorants and mosquito repellent vaporizers. However, the worst harm that can be done by Air pollution to a human being is done through PM 2.5 and PM 10 particles. Amongst these too, PM 10 particles can somewhat still be blocked by the sensory system, nasal hair and mucus but PM 2.5 particles are way to small to have been filtered out. PM 2.5 simply refers to particles in the air which are lesser than 2.5 microns in size. This is roughly around 1/40th the diameter of 1 human hair strand. These particles can simply enter our respiratory system through the air we breathe in. These then can lodge themselves in our bronchi-oles and hamper proper breathing. Over time they can also block the functioning of our lungs leading to several health hazards and even death in few cases.

It is a misconception to believe that one is protected from air pollution if they lock their doors and stay home. In fact, the Crusaders PM 2.5 detector review made us aware of how in reality, indoors are much more polluted than the open outdoors. This is because with continuous, free flowing wind outside can potentially take away and disperse the pollutants. However, in our homes and offices, these pollutants (including dust and pollen etc) fall onto the furniture and get lodged there. When we use the fan to cool off, we are also providing movement to these pollutant particles which then are breathed in by us.

The Crusaders PM 2.5 Detector does a wonderful job of giving us a reality check. There are times when we feel suffocated or nauseous inside our house. A quick reading on the Crusaders PM 2.5 Detector indicates that our surroundings may have been quite full of pollutants. This in turn reinforces the need to have air purifiers installed in the places we work and sleep in. Atleast this is quite important if one lives in cities like Delhi, Mumbai etc.

Crusaders PM 2.5 Detector Review

Crusaders PM 2.5 Detector device from Crusaders Technologies uses laser particle sensors, which are more accurate as compared to normally available dust sensors using IR and can be used to check air quality in rooms, cars, public areas, etc.

The device can easily fit in your pocket and we used it around the infamously polluted capital city a.k.a. New Delhi and were mostly left stumped by how bad was the air we were regularly breathing.

The device is quite simple to use. On the top side it has an Air inlet and Air outlet which then checks the quality of air in our surroundings.


One side of the device has a micro USB charging port for recharging the device. The Crusaders PM 2.5 Detector can run for around 4 hours continuously on one full charge.


However if you want to just check the air quality a couple of times a day and not continuously, the device can well last a week. The front of the device has a circular screen and a single tactical button at the bottom right corner.

To switch on the device one has to hold the blue tactile button for 3 seconds. Crusaders PM 2.5 Detector boots up immediately and gives the reading for 2 mins after which it shuts down automatically or can be shut down by holding the button for another 3 seconds.

Quickly pressing the same button twice while the device is on will keep it on until the battery dies out. Crusaders PM 2.5 Detector has a large screen and the information displayed it simple to understand.

The screen also shows a “Green smiley” when the air pollution level is 0-50 (Good), a “Yellow smiley” when it is 50-150 (Moderate) and a “Red Sad Smiley” when it is above 150 (Unhealthy).

We tested the device in multiple places and got a plethora of results.


Delhi, mostly being extremely polluted, never went below 200-300. The reading on the Crusaders PM 2.5 Detector for our living room was 180 while on our open balcony it went up to 250+. Stuck in a traffic jam, the Crusaders PM 2.5 Detector gave a reading of 359 while intriguingly, while sitting near a havan-pooja during Dussehra festival the detector was maxed at a staggering 999 reading continuously.

We found the device quite effective in its reading as when the air purifier was switched on in the room, the reading on the Crusaders PM 2.5 Detector went down from 211 to 78 in 15-20 minutes.


The device, on its screen had a bluetooth symbol too, however nothing regarding this is mentioned anywhere in the manual of the Crusaders PM 2.5 Detector and maybe in future with a firmware upgrade, one could even transfer this data to their smartphones or PCs.

Our verdict – Crusaders PM 2.5 Detector Review

The Crusaders PM 2.5 Detector is priced at Rs 4,999. This might prove to be a deterrent for many potential buyers. Alot of air purifiers come with their own detectors in which case the use of a separate one is obliterated. However, if you wish to carry around a portable one or maybe keep a check on the air in your surroundings then this is the device for you. We would like to say that it is quite a useful little gadget if you live in highly polluted cities like Delhi, Gwalior, Mumbai etc.

Key specifications – Crusaders PM 2.5 Detector Review

  • 66 gms in weight
  • Laser scattering technique
  • 0-999 microgram/m3 range measuring range
  • response time < 5s
  • Li-ion battery 500 mAh
  • work time >4hours
  • auto – standby option in case of ideal time of 2 minutes.