Air pollution is no longer a Delhi-NCR phenomenon. Unhealthy air due to relentless construction activity and vehicular exhausts is also the norm in cities such as Mumbai, Patna, Varanasi, Kolkata, Hyderabad, etc. In fact, a recent study said that air pollutions levels in Lucknow and Patna matched that of the national capital. The fallout is that respiratory illness, cardiac ailments and lung diseases are on the rise due to the worsening air pollution levels in India. No wonder, air quality management products like air purifiers and masks are in high demand. Air purifiers are in demand these days because they quickly and quietly clear allergens and other particles, effectively remove odour, pollen, smoke, dust, pet dander, and almost all other pollutants present in the air. The top brands in the air purification segment are doing their bit to spread the word and awareness around the concern. New Delhi-based Crusaders Technologies, a leading player in the portable air purifier segment, has debuted an innovative air purifier that has a digital laser PM 2.5 air quality indicator. This is the XJ-4001B machine that can make a real-time display of PM 2.5 data in your room. It retails for Rs 33,500 and will find good use in your home or office, even in hospitality, medical and lifestyle segments. We got the XJ-4001B air purifier for a product evaluation; let us check out whether it delivers on its promise of giving us pure and fresh air. Out of the box, the XJ-4001B comes across as a pleasing and neat-looking piece of equipment that will not look odd in your office space or the living room. I installed the device in my daughter\u2019s bedroom for over two weeks now and take my word, this Crusaders air purifier is pretty adept in making the room pollution-free. However, keep the doors and windows shut when you switch it on. The XJ-4001B is significantly big in size compared to other offerings. It measures 402 x 186 x 624 mm in body dimensions and weighs 8 kg. Despite this, it is extremely easy to move around and operate. It can cover upto 850-900 square feet. This air purification system is based on the principle of FDA approved technology called PCO (photo-catalytic oxidation) along with high grade HEPA (high-efficiency particulate air) and carbon filter to neutralise dust, pollen allergen, smoke, odour, bacteria, virus, other micro-organisms, and toxic gases such as formaldehyde. Technical speak, it has a six-stage physical filtration system. This comprises a pre-filter, activated carbon filter, HEPA filter, photo catalyst (TiO2) filter, UV irradiation and negative ions. HEPA is a filter which can trap 0.3 micron size of particle with an efficiency of 99.97%. This type of filter has the efficiency to catch and trap indoor carcinogens particles like PM 2.5 particulates, pollen, allergens, surface adhering mold, fine dust and clinging odours like cigarette smoke, foul smells or pet odour. Switched on, the XJ-4001B comes to life in an instant. There are various modes for you to select\u2014smart auto mode, night mode, silent mode, wind speed adjustment, timer mode, smart UV and anion mode. I set the air purifier in silent mode and kept the wind speed at the lower level and what impressed me most was the machine\u2019s extremely silent operation. The PM 2.5 air quality indicator will give you real time reading for PM 2.5 size of particle (40 times smaller than the width of your hair). You may also like to watch this video Takeaways: The XJ-4001B air purifier does a good job at improving the quality of air indoors and gives healthier air. It is somewhat expensive but is a must-have equipment for those living in smog-infested regions, as well as for those people with allergies and respiratory diseases.