Background Although hand-arm vibration syndrome has traditionally been reported more frequently in colder northern regions, recent cases in Guangdong Province, a subtropical region in the south, exhibit a certain degree of clustering in terms of industry distribution and company size, and for a period of time, they account for a high proportion of the total number of cases reported nationwide. Objective To describe the occupational exposure profile of hand-transmitted vibration (HTV) in Guangdong Province in 2025 and to compare exposure levels across industries, enterprise sizes, and occupational categories. Methods Data were sourced from the Guangdong Provincial Occupational Health Quality Control Platform, to which occupational health technical service institutions across Guangdong Province submitted relevant reports in 2025. The dataset included employers with documented HTV hazards, measurement results, and the number of exposed workers. Exposure levels were categorized into four grades according to the 4-h energy-equivalent frequency-weighted vibration acceleration: Grade I (<1 m·s⁻²), Grade II (1-2.5 m·s⁻²), Grade III (>2.5-5 m·s⁻²), and Grade IV (>5 m·s⁻²). Results A total of 12468 employers with identifiable HTV exposure were identified through the platform in 2025, of which 11710 (93.92%) were in the manufacturing sector. By enterprise scale, 274 (2.20%) were large, 934 (7.49%) were medium-sized, 8 749 (70.17%) were small, and 2511 (20.14%) were micro-sized enterprises, with small enterprises accounting for the largest proportion. Among 22298 job posts with identified HTV exposure, grinding, assembly, polishing, burnishing, and welding were the most common tasks. The M (P₂₅, P₇₅) 4-h energy-equivalent frequency-weighted acceleration [a(4)] was 2.1 (1.5, 2.7) m·s⁻², with values ranging from 0.1 to 16.2 m·s⁻². Exposure levels were distributed as follows: Grade I, 2835 posts (12.71%); Grade II, 12761 posts, (57.23%); Grade III, 6690 posts, (30.00%); and Grade IV, 12 posts (0.05%), with Grade Ⅱ posts accounting for the largest proportion. Within the manufacturing sector, 21013 exposed job posts were identified, accounting for 94.24% of all exposed posts. Twelve job posts exceeded the occupational exposure limit, of which nine were polishing positions. A total of 115955 workers were exposed to HTV, primarily in manufacturing (110879; 95.62%). Among the exposed workers, 21237, 23454, 65047, and 6217 were employed in large, medium, small, and micro-sized enterprises, respectively. Grinding, assembly, polishing, deburring, and welding were the five most common occupational categories among the exposed workers. The distribution of worker by exposure grade was similar to that of exposed posts: Grade I, 11921 workers (10.28%); Grade II, 65463 workers (56.46%); Grade III, 38447 workers (33.16%); and Grade IV, 124 workers (0.11%). Conclusion In Guangdong Province, HTV exposure is mainly concentrated in the manufacturing sector, particularly in metal product manufacturing, and commonly involves tasks such as grinding, assembly, and polishing. Both exposed enterprises and exposed workers are predominantly concentrated in small enterprises. Grade II exposure accounts for the largest proportion of both exposed job posts and exposed workers, and some workers are at a risk of developing hand-arm vibration syndrome. These findings suggest that targeted occupational management and comprehensive control measures should be strengthened to reduce HTV exposure and prevent hand-arm vibration syndrome.

OBJECTIVE: To analyze the influence of noise measuring skills by continuous inter-laboratory comparison among occupational hygiene technical service organizations. METHODS: The results of 68, 55 and 50 occupational hygiene technical service organizations(reference organizations) participating in the inter-laboratory comparison of workplace noise measurement in 2014, 2017 and 2018 respectively were collected. The measurement operation and the calculation of equivalent sound level were evaluated according to the GBZ/T 189.8-2007 Measurement of Physical Agents in Workplace--Part 8: Noise.The measured results were analyzed by z score evaluation method. RESULTS: The results of noise measurement field operation of the reference organizations in the year 2014, 2017 and 2018 show that the accuracy rates of instrument setting was 89.7%, 98.2% and 100.0%, the accuracy rates of measuring position were 52.9%, 81.8% and 94.0%, the accuracy rates of sound level meter holding were 54.4%, 80.0% and 92.0%, the accuracy rates of microphone pointing were 98.5%, 98.2% and 94.0%, and the accuracy rates of noise type recognition were 83.8%, 92.7% and 84.0%, respectively. Among them, the accuracy of instrument setting, measurement position and sound level meter holding showed an increasing trend year by year(P<0.01). The pass rates of measurement results were 91.2%, 94.5% and 88.0% in 2014, 2017 and 2018 respectively. The pass rates of equivalent sound level calculation were 73.5%, 92.7% and 88.0%. The pass rates of comprehensive evaluation were 70.6%, 89.1% and 80.0% respectively. Among them, the pass rates of equivalent sound level calculation and comprehensive evaluation in 2017 were higher than that in 2014(P<0.017). There was no significant difference in the three-year comprehensive assessment total pass rate between private organizations and non-private organizations(84.0 % vs 75.5%, P>0.05). There was no significant difference in the total pass rate of three-year comprehensive evaluation between non-Pearl-River-Delta organizations and Pearl-River-Delta organizations(70.3% vs 81.6%, P>0.05). CONCLUSION: Continuous inter-laboratory comparison in occupational hygiene technical service organizations is beneficial to improve on-site noise measure capability.

OBJECTIVE: To evaluate the feasibility of the inter-laboratory comparison of microwave radiation measuring instruments which uses cellphone signal shielding device as standard source,and to establish inter-laboratory comparison method of microwave radiation.METHODS: The typical sampling method has been used by selecting twenty-one measuring instruments of microwave radiation from 21 occupational hygiene technical service organizations as study subjects.A cellphone signal shielding device was applied as standard source.Measurement points were measured by surveyors at a distance of 1.0 and 1.5 meter to the standard source,and the measurement results were analyzed by four robust technology and z-score evaluation method.RESULTS: Stability test showed that there was no statistical difference among the power density of standard source which were measurement at three diffluent time [(26.10 ± 0.94) vs(25.78 ± 0.27) vs(25.83 ±0.47) μW/cm~2,P>0.05].The standard source stability can also satisfy the requirement of inter-laboratory comparison.Among the 21 selected equipments,one of the 21 measuring instruments was not calibrated,one calibration certificate of the instruments was expired,and one calibration result of the instruments was unqualified.The z score of inter-laboratory(z_B) of 21 measuring instruments ranged from-1.27 to 4.85,while z score of within-laboratory(z_w) ranged from-1.42 to 2.18.One | z_B| of the instruments was above 3.00,while | z_W| was above 2.00.Comprehensive evaluation of the above results showed that only one instrument was unqualified.CONCLUSION: It is feasible that a cellphone signal shielding device could be applied as standard source.The method developed in this study can be used to understand the performance of microwave radiation instruments.